CONST

Define a named constant. Suffixes $ % ! set the type.

CONST name = expr

name - constant name expr - value expression

Example:

CONST MAX = 21
CONST TITLE$ = "HELLO"
CONST FLAG% = 1
PRINT MAX * 2, TITLE$, FLAG%

Source: docs/help/const.txt inmmcore. On the computer, typeHELP CONST.